Many LT1 owners use Mobil 1 oil. I think your engine requirement was for 10W-30 originally.

This is my opinion: I see no reason to go with the synthetic motor oil in most cases. I use conventional oil in both my van and Impala. I change the oil about 4-5K miles. I also use a larger filter on each one, gives extra capacity for oil and larger filter media surface to capture the dirt more easily and for cost there is no difference between the short or long filters.

One thing most people will agree on is having your oil analyzed by a company that will give you the results of your motor and show you what the average engine of your type and mileage should show in the results. These reports will help you see what your own engine is doing over a period of time. Personally I do not use oil analyzes.

Been awhile since I spent time there but there is a forum known as "Bob is the oil guy" I foget the exact link but can come up with it. At any rate guys obsess over oils and the M1 5w-30 everyone thinks is awesome for the LT1 is really absolutely nothing special IN THIS ENGINE, it actually results in fairly high iron wear compared to cheaper oils or other synthetics. It is a quality oil and wont do any harm but Used Oil Analysis has shown it to not be worth the money in this engine.

The oil that tests the best in this engine and the LS motors in Castrol Syntec 0w-30 specifically labeled "Made in Germany", pretty specific and can be tough to find, AutoZone is often a good bet if you want to go hunting. Really though any SM rated oil ranging from 0w-30 to 10w-40 will be just fine and I have even run 15w-40 in summer.

FWIW the Castrol syntec 0w-30 is much thicker at operating temps than the M1 5w-30.

i have 1996 impala and i currently use mobil 1 full synthetic 5w-30 oil is that a good oil for a stock motor does the weight of the oil matter and does full synthetic or conventional matter

Chevrolet engineers recommend the 5W-30 viscosity for your cars engine, so you're good to go there.

Mobil 1 is a synthetic oil and one of the better ones on the market. You can't go wrong with Mobil 1. In fact, Many GM vehicles come factory equipped with Mobil 1 synthetic oil. There are many advantages a good synthetic oil offers vs a petroleum oil and these include; 1. Lower engine temperatures. 2. More power/better throttle response. 3. Improved fuel economy and with the price of gas these days any improvement in fuel economy is very welcomed! 4. Lower emissions. 5. Easier winter starting and improved cold temperature engine protection. 6. Improved high temperature engine protection. There are other benefits as well. I've been using nothing but synthetic oils in all my vehicles for the past 25 years and I will never go back to the dark days of using dead dinosaur oils ever again. They are too expensive to use and have so many drawbacks compared to a good quality synthetic oil, it's just not worth it. Engines cost too much to replace.

Below is a very interesting article on this subject, complete with photographs and test results. Enjoy -

I also use a larger filter on each one, gives extra capacity for oil and larger filter media surface to capture the dirt more easily and for cost there is no difference between the short or long filters.

I beleive the oem spec filter is PF-52... what is the longer filter?

Not tryign to hijack the thread... but what weight of conventional do you use? I use 10w40, well aware that that's heaver than spec... but it's got 180,000 miles.

Not tryign to hijack the thread... but what weight of conventional do you use? I use 10w40, well aware that that's heaver than spec... but it's got 180,000 miles.

I don't know what the AC Delco number is but look for the truck 305/350 oil filter. On Fram the original size for my car engine is a PH30 and truck option is PH5. The 5 is at least half the length longer than the 30 is.